Method of assembling mirror reflective element sub-assembly for exterior rearview mirror assembly

ABSTRACT

A method for assembling a mirror reflective element sub-assembly for a vehicular exterior rearview mirror assembly includes providing a support fixture having locator pins disposed at apertures thereof and protruding therefrom. The locator pins are received through corresponding apertures of a heater pad and through corresponding apertures of a back plate to align the back plate at the heater pad at the support fixture. A mirror reflective element is attached at the back plate and heater pad construction, and that construction is disposed at a laser ablation fixture, whereby the locator pins of the laser ablation fixture are received through the apertures of the back plate to align the construction at the laser ablation fixture. After an indicator icon is laser ablated through the mirror reflector, the construction is removed from the laser ablation fixture, and an indicator module is snap attached at a receiving portion of the back plate.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority of U.S. provisional applicationSer. No. 62/878,407, filed Jul. 25, 2019, which is hereby incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to the field of rearview mirrorassemblies for vehicles.

BACKGROUND OF THE INVENTION

It is known to provide an automotive rearview mirror assembly thatincludes one or more accessories, such as a light source or blind spotindicator or turn signal indicator. The mirror reflective element ofsuch known mirror assemblies include a mirror reflector coating that isvacuum deposited or sputter coated onto a surface of a glass substrateof the mirror reflective element and typically includes visualindicators such as turn signal indicators and blind zone indicators thatindicate to a driver presence of another overtaking vehicle in a sidelane adjacent to the equipped vehicle.

SUMMARY OF THE INVENTION

The present invention provides a method or process or system forassembling a mirror reflective element sub-assembly for a vehicularexterior rearview mirror assembly utilizing nest fixtures and locatorpins and corresponding apertures to ensure alignment of the componentsduring the assembly process and the indicator icon forming process. Thesystem or method uses a support fixture having locator pins disposed atapertures thereof and protruding therefrom, with a heater pad disposedat the support fixture such that the locator pins protrude through orare received in or through corresponding apertures of the heater pad toalign the heater pad at the support fixture. A back plate is disposed atthe heater pad and support fixture, such that the locator pins protrudethrough or are received in or through corresponding apertures of theback plate to align the back plate at the heater pad at the supportfixture. The back plate is attached at the heater pad and the back plateand heater pad construction is removed from the support fixture and amirror reflective element is attached at the back plate and heater padconstruction. A laser ablation fixture is provided that includes locatorpins disposed at apertures thereof and protruding therefrom. The mirrorreflective element and back plate and heater pad construction isdisposed at a laser ablation nest or fixture, such that the locator pinsof the laser ablation fixture protrude through or are received in orthrough the apertures of the back plate to align the reflective elementand back plate and heater pad construction at the laser ablationfixture. An indicator icon is established (via laser ablation) throughthe mirror reflector of the mirror reflective element. After theindicator icon is laser ablated through the mirror reflector, thereflective element and back plate and heater pad construction is removedfrom the laser ablation fixture and an indicator module is snap-attachedat a receiving portion of the back plate, whereby the indicator moduleis aligned with the indicator icon laser ablated through the mirrorreflector.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of an exterior rearview mirror assembly in accordancewith the present invention;

FIG. 2 is an exploded view of an assembly fixture for assembling theback plate and heater pad sub-assembly;

FIG. 3 is an exploded view of a fixture for holding the mirrorreflective element sub-assembly for laser ablating the indicator icon;

FIG. 4 is a sectional view of the alignment fixture of the assemblyfixture of FIG. 2;

FIG. 5 is a plan view of the alignment fixture, with a heater paddisposed thereat;

FIG. 6 is a plan view of the alignment fixture, with a back platedisposed at the heater pad;

FIG. 7 is a plan view of the mirror reflective element sub-assembly;

FIG. 8 is a sectional view of the fixture holding the mirror reflectiveelement sub-assembly for the laser ablation process;

FIG. 9 is a plan view of the completed mirror reflective elementsub-assembly, with a blind zone indicator module attached at the backplate;

FIG. 10 is an exploded view of the blind zone indicator module;

FIGS. 11A-G show the process of assembling the blind zone indicatormodule; and

FIG. 12 is a perspective view of the alignment fixture.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depictedtherein, an exterior rearview mirror assembly 10 for a vehicle 11includes a mirror reflective element 12 received in and/or supported ator by a mirror shell or casing or head portion 14 (FIG. 1). The mirrorcasing or head portion 14 may be fixedly attached at a mounting arm orbase 16 at the side of the vehicle or may be movably mounted to amounting arm or base or portion 16, and may comprise a breakaway mirror(where the mirror head portion may be manually pivoted about themounting arm or base) or may comprise a powerfold mirror (where themirror head portion may be pivoted via an actuator assembly oradjustment device). Mounting arm or base 16 of mirror assembly 10 ismounted at the side 11 a of a host or subject vehicle 11, with thereflective element 12 providing a rearward field of view along therespective side of the vehicle to the driver of the vehicle, asdiscussed below. A blind spot indicator icon 18 is established at thereflective element 14 (such as by laser ablating the mirror reflector atthe glass substrate of the reflective element), with an indicator module20 (FIGS. 10 and 11G) disposed behind the mirror reflective element atthe indicator icon 18.

In the illustrated embodiment, the coated glass substrate (coated with amirror reflector at a side or surface thereof) of the mirror reflectiveelement has a heater pad 22 disposed at its rear surface, and a backplate 24 attached at the heater pad and/or glass substrate, such thatthe heater pad is sandwiched between the back plate and the glasssubstrate. The back plate and heater pad each have an aperture throughwhich the indicator module 20 emits light that passes through the mirrorreflective element at the indicator icon 18 for viewing by the driver ofthe vehicle equipped with the exterior rearview mirror assembly. Themirror back plate comprises a plastic injection-molded back plate havinga generally planar attaching surface (to which the heater pad isadhered) and an opposite side or surface that is formed (via plasticinjection molding) for attachment of the mirror reflective elementsub-assembly to an actuator of an exterior rearview mirror assembly. Themirror back plate may be formed or molded with a circumscribing liparound a perimeter of the attaching side or surface, whereby the lipcircumscribes the peripheral edge of the mirror reflective element orglass substrate adhered to the heater pad. Optionally, the back platemay not include such a lip, whereby the perimeter edge of the mirrorglass substrate may be rounded (such as with a radius of curvature of atleast 2.5 mm) and exposed to provide a continuous transition between theplanar front surface of the glass substrate to a side perimeter surfaceof the back plate or of the mirror casing.

During assembly of the mirror reflective element sub-assembly(comprising the mirror reflective element and heater pad and backplate), and as can be seen with reference to FIGS. 2-9, a base plate 26,pad support 27, bearing support plate 28 and nest 30 are provided toalign and retain the components during the assembly process that formsthe reflective element sub-assembly. As shown in FIGS. 4 and 5, thealignment fixture is assembled with a 4-way locator pin 32 (whichprecludes relative movement in four directions) and a 2-way locator pin34 (which precludes relative movement in two directions, while allowingrelative movement in two opposite directions, such as via a pin beingreceived in a small slot), with the pins 32, 34 protruding from the baseplate 26, through corresponding apertures in the pad support 27 so as tobe at a heater pad support surface of the pad support 27. The heater pad22 is selected and placed at the alignment fixture and aligned using thelocator pins 32, 34, which are received through apertures 22 a, 22 bthrough the heater pad 22. A liner or film or cover element is removedfrom the rear side of the heater pad and the back plate 24 is aligned(using the locator pins 32, 34 and apertures 24 a, 24 b of the backplate 24) at the heater pad and alignment fixture and adhered to theheater pad (FIG. 6). When aligned and attached, the receiving portion 24c (for receiving the indicator module 20) of the back plate 24 (thatreceives the indicator module 20 therein) is aligned with the iconaperture 22 c of the heater pad. As can be seen with reference to FIG.6, the icon aperture 22 c of the heater pad is within and aligned withthe aperture of the receiving portion 24 c of the back plate.

The back plate and heater pad sub-assembly is then removed from thealignment fixture and the coated glass substrate (the reflectiveelement) is adhered to the heater pad after the liner from the frontside of the heater pad has been removed (FIG. 7) to form the reflectiveelement sub-assembly 36. The positioning of the reflective element atthe back plate may be established via a lip at the back plate thatcircumscribes the perimeter edge of the reflective element or via othersuitable means. The positioning of the reflective element need not be asprecise as the relative positioning of the heater pad and back plate,since the icon or aperture has not yet (at the time the reflectiveelement is attached at the back plate) been established at or throughthe mirror reflector coating of the mirror reflective element.

After the reflective element sub-assembly is assembled, the sub-assembly36 is loaded into a nest plate 38 (FIGS. 3 and 8) and aligned thereatvia locator pins 40, 42 that are received at the same apertures of theback plate as locator pins 32, 34 were during the assembly process. Thesub-assembly is disposed at a recess of the nest plate, with the backplate received in the recess and the reflective element exposed. Thelocator pins 40, 42 protrude from the alignment plate 44 and arereceived in and through corresponding apertures of the nest plate 38 soas to be received through the apertures 24 a, 24 b of the back plate 24as the sub-assembly 36 is loaded into the nest plate 38. The locatorpins 40, 42 comprise 2-way and 4-way locator pins that are receivedthrough corresponding apertures in the nest plate 38 and in thealignment plate 44. As shown in FIGS. 3 and 8, the nest plate 38 isaligned with the alignment plate 44 (via the locator pins) such that theapertures (including the apertures for the locator pins and the aperturefor the indicator module and indicator icon) of the back plate alignwith the apertures at the nest plate and alignment plate. The nest orrecess holds the sub-assembly by the profile of the back plate andreflective element (so that the sub-assembly does not move laterally orin the x or y direction relative to the nest plate) and optionally mayinclude vacuum suction or suction cups 39 (FIG. 12), and may include asuction port that connects to a vacuum supply line 39 a, to hold thesub-assembly in the z-direction (so the sub-assembly does not moveupward and out of the nest plate) during the laser ablation process.

After the sub-assembly is loaded into the nest plate, the sub-assemblyis positively located and fixed relative to the nest plate and alignmentplate with a laser ablation tool or device also positively positionedrelative to the nest plate and alignment plate (and having a knownlocation relative to the alignment plate). The laser ablation tool ordevice is operated to laser ablate (establish) the indicator icon shapeat a set location relative to the alignment plate and thus at theappropriate location on the reflective element relative to the iconaperture of the heater pad. The laser ablation tool or device mayoperate to laser ablate the indicator icon shape from the first surfacereflector of the reflective element (such as a thin metalliclight-reflecting layer established or coated or deposited at the frontor first surface of the glass substrate that is closer to the driver ofthe vehicle when the mirror assembly is mounted at the vehicle). Inother words, the indicator icon is formed through the mirror reflectorby removing a portion of the mirror reflector from the surface of theglass substrate that faces away from the back plate (and that is facingupward in FIG. 8). Optionally, and such as shown in FIG. 12, the systemmay include an air knife 46 at one side of the fixture or nest plate anda vacuum 48 at the other side of the fixture or nest plate, whereby theair knife blows forced air across the surface of the reflective elementto remove particulates that get emitted or removed from the coated glasssurface during the laser ablation process, with the vacuum drawing theair and particulates in so the particulates are removed from thereflective element.

The icon is thus formed at the mirror reflective element at a preciselocation relative to the indicator module receiving portion of the backplate (as is known via the location of the locator pins and location ofthe alignment plate relative to the laser ablation device). After theindicator icon is formed (via laser ablation) at the reflector-coatedsurface of the mirror reflective element, the sub-assembly is removedfrom the nest and a blind zone indicator or blind spot indicator module20 is selected and snapped into the receiving portion at the rear of theback plate (see FIG. 9).

Thus, the nests and plates provide for precise alignment of the backplate with the heater pad, and precise positioning of the sub-assembly(with the mirror reflective element attached at the back plate andheater pad) relative to the laser ablation device, such that the laserablation of the icon at and through the reflector coating is at aprecise location relative to the pin-receiving apertures formed throughthe heater pad and the back plate and relative to the icons or indicatorapertures at the heater pad and the back plate. In the illustratedembodiment, the pins and the pin-receiving apertures are established atand adjacent to the indicator module aperture (such as at corners of theaperture).

In the illustrated embodiment, the indicator icon is established througha first surface reflector coating at the outermost surface of the glasssubstrate of the mirror reflective element, with the aperture throughthe nest plate being at and behind the laser ablating area so that thelaser doesn't etch the fixture over time and repeated use. Optionally,the indicator icon may be formed through a mirror reflector at the rearsurface of the coated glass substrate that faces toward the back plate.In such a configuration, the laser ablation device accesses the coatedrear surface of the glass substrate through the apertures formed throughthe alignment plate and the nest plate (and through the indicator modulereceiving structure and aperture of the back plate and through theindicator aperture of the heater pad).

As shown in FIGS. 10 and 11A-G, the indicator module 20 includes ahousing 48 (FIG. 11A), and a selected printed circuit board assembly(PCBA) 50 is settled in or disposed into a rear receiving part of thehousing (FIG. 11B). The housing and PCBA sub-assembly is placed on aheat staking fixture to heat stake (such as at location 50 a) the PCBAat the housing (FIG. 11C). The housing and PCBA sub-assembly is then puton a potting tray and potting material 52 is added to seal the PCBA inthe housing (FIG. 11D). The housing and PCBA sub-assembly (with pottingmaterial) is then moved to a taping fixture (FIG. 11E) where thediffuser assembly 54 is applied. As shown in FIG. 11F, the diffuserattachment tape 54 a, diffuser 54 b, mask 54 c and release liner 54 dare assembled together (FIG. 11F) and aligned and taped at the frontside of the housing at the taping fixture (FIG. 11G). The assembledindicator module 20 is then tested using end of line testing (EOLT) toverify current draw and then, when selected during assembly of thereflective element sub-assembly, the indicator module is snapped intothe receiving portion at the rear of the back plate.

Therefore, the assembly process of the present invention utilizeslocator pins and a nest and support fixture for aligning and retainingthe heater pad and back plate during attachment of the heater pad at thefront side of the back plate, and utilizes locator pins and a nest andalignment fixture for aligning and retaining the mirror reflectiveelement sub-assembly during the laser ablation of the mirror reflectorto establish an indicator icon at the reflective element. The locatorpins comprise a 2-way locator pin (that locates and limits movement intwo lateral direction and that allows movement in the other lateraldirection, such as by being received in a slotted aperture) and a 4-waylocator pin (that locates and limits movement in all lateral directions,such as by being received in an aperture that is sized and shaped tocorrespond with the cross dimension and shape of the pin). The locatorpins of the support fixture function in the same manner as the locatorpins of the laser ablation fixture, such that the icon region of thereflective element and heater pad are aligned with the back plateaperture or receiving portion, such that the icon is established throughthe mirror reflector at the correct and precise location for lightemitted by the indicator module to pass therethrough when the mirrorassembly is mounted at a vehicle. The two-way locator pin allows someslight adjustment to align the four-way locator pin with the aperture(s)to properly and accurately set and retain the components in therespective fixtures for assembly and/or laser ablation. After thesub-assembly is held at the laser ablation station, the icon is laserablated at the reflector and the sub-assembly is removed from the nestplate and the indicator module is attached (such as snap-attached) atthe rear of the back plate.

The indicator module may utilize aspects of the indicators and/or lightmodules and/or systems described in U.S. Pat. Nos. 8,764,256; 8,242,896;7,720,580; 7,626,749; 7,581,859; 7,492,281; 7,038,577; 6,882,287;6,582,109; 6,276,821; 6,227,689; 6,198,409; 6,176,602; 5,929,786;5,823,654; 5,786,772, 5,669,699; 5,497,306 and/or 5,371,659, and/or U.S.Publication No. US-2013-0242586, which are hereby incorporated herein byreference in their entireties.

The heater pad or element at the rear surface of the glass substrate maycomprise a mirror defrost/demisting heater and may provide ananti-fogging of de-fogging feature to the exterior mirror assembly, andmay utilize aspects of the heater elements or pads described in U.S.Pat. Nos. 9,481,304; 8,173,936; 8,058,977; 7,400,435; 5,808,777;5,610,756 and/or 5,446,576, which are hereby incorporated herein byreference in their entireties.

The glass substrate (that is coated with the mirror reflector andfixtured via the alignment fixtures and laser ablated as discussedabove) may comprise a single glass substrate for a single substratenon-electro-optic or non-variably reflectant reflective element, such asa flat glass substrate or curved glass substrate with a first (front)surface mirror reflector (disposed at the first or front or outermostside or surface of the glass substrate) or with a second (rear) surfacemirror reflector (disposed at the second or rear side or surface of theglass substrate). Optionally, the glass substrate (that is coated withthe mirror reflector and fixtured via the alignment fixtures and laserablated as discussed above) may comprise a rear glass substrate for anelectro-optic or electrochromic reflective element, whereby a frontglass substrate is mated with the rear glass substrate (with anelectro-optic medium sandwiched therebetween) to form an electro-opticmirror reflective element or cell.

The mirror assembly may comprise any suitable construction, such as, forexample, a mirror assembly with the reflective element being nested inthe mirror casing and with the mirror casing having a curved or beveledperimeter edge around the reflective element and with no overlap ontothe front surface of the reflective element (such as by utilizingaspects of the mirror assemblies described in U.S. Pat. Nos. 7,255,451;7,289,037; 7,360,932; 8,049,640; 8,277,059 and/or 8,529,108), or such asa mirror assembly having a rear substrate of an electro-optic orelectrochromic reflective element nested in the mirror casing, and withthe front substrate having curved or beveled perimeter edges, or such asa mirror assembly having a single substrate reflective element that isdisposed at an outer perimeter edge of the mirror casing and with thesingle glass substrate having curved or rounded perimeter edges, such asdescribed in U.S. Pat. Nos. 8,508,831; 8,730,553; 9,598,016 and/or9,346,403, and/or U.S. Publication Nos. US-2014-0313563 and/orUS-2015-0097955, which are hereby incorporated herein by reference intheir entireties (and with electrochromic and prismatic mirrors of suchconstruction are commercially available from the assignee of thisapplication under the trade name INFINITY™ mirror).

The rearview mirror assembly may comprise a mirror assembly of the typesdescribed in U.S. Pat. Nos. 7,420,756; 7,289,037; 7,274,501; 7,338,177;7,255,451; 7,249,860; 6,318,870; 6,598,980; 5,327,288; 4,948,242;4,826,289; 4,436,371 and 4,435,042, which are hereby incorporated hereinby reference in their entireties. A variety of mirror accessories andconstructions are known in the art, such as those disclosed in U.S. Pat.Nos. 5,555,136; 5,582,383; 5,680,263; 5,984,482; 6,227,675; 6,229,319and 6,315,421 (which are hereby incorporated herein by reference intheir entireties), that can benefit from the present invention.

Changes and modifications in the specifically described embodiments maybe carried out without departing from the principles of the presentinvention, which is intended to be limited only by the scope of theappended claims as interpreted according to the principles of patentlaw.

1. A method for assembling a mirror reflective element sub-assembly fora vehicular exterior rearview mirror assembly, said method comprising:providing a support fixture having locator pins disposed at aperturesthereof and protruding therefrom; providing a heater pad at the supportfixture, whereby the locator pins of the support fixture are receivedthrough corresponding apertures of the heater pad to align the heaterpad at the support fixture, wherein the heater pad comprises anindicator aperture; providing a back plate at the heater pad and supportfixture, whereby the locator pins of the support fixture are received incorresponding apertures of the back plate to align the back plate at theheater pad at the support fixture, wherein the back plate comprises anindicator aperture that, with the locator pins received through thecorresponding apertures of the back plate and the heater pad, is alignedwith the indicator aperture of the heater pad; attaching the back plateat the heater pad; removing the back plate and heater pad constructionfrom the support fixture; attaching a mirror reflective element at theback plate and heater pad construction, wherein the mirror reflectiveelement has a mirror reflector coated at a surface thereof; providing alaser ablation fixture having locator pins disposed at apertures thereofand protruding therefrom; disposing the mirror reflective element andback plate and heater pad construction at the laser ablation fixture,whereby the locator pins of the laser ablation fixture are receivedthrough the apertures of the back plate to align the mirror reflectiveelement and back plate and heater pad construction at the laser ablationfixture; laser ablating an indicator icon through the mirror reflectorof the mirror reflective element at the aligned indicator apertures ofthe back plate and the heater pad; after the indicator icon is laserablated through the mirror reflector, removing the mirror reflectiveelement and back plate and heater pad construction from the laserablation fixture; and attaching an indicator module at a receivingportion of the back plate, whereby the indicator module, when attachedat the receiving portion of the back plate, is aligned with theindicator icon laser ablated through the mirror reflector.
 2. The methodof claim 1, wherein the mirror reflector is established at the surfaceof the mirror reflective element that is opposite from the surface thatopposes the heater pad.
 3. The method of claim 2, wherein the laserablation fixture comprises structure having an aperture therethroughthat corresponds with the location of the indicator icon that is laserablated through the mirror reflector when the mirror reflective elementand back plate and heater pad construction is disposed at the laserablation fixture.
 4. The method of claim 1, wherein the mirror reflectoris established at the surface of the mirror reflective element thatopposes the heater pad.
 5. The method of claim 1, wherein the locatorpins at the support fixture comprise cylindrical pins, and wherein thecorresponding apertures of the heater pad and of the back plate comprisea circular aperture and a slotted aperture to provide 4-way locating and2-way locating of the heater pad and back plate at the support fixture.6. The method of claim 5, wherein the locator pins at the laser ablationfixture comprise cylindrical pins, and wherein the correspondingapertures of the back plate comprise a circular aperture and a slottedaperture to provide 4-way locating and 2-way locating of the back plateat the laser ablation fixture.
 7. The method of claim 1, wherein thelocator pins at the laser ablation fixture comprise cylindrical pins,and wherein the corresponding apertures of the back plate comprise acircular aperture and a slotted aperture to provide 4-way locating and2-way locating of the back plate at the laser ablation fixture.
 8. Themethod of claim 1, wherein attaching the back plate at the heater padcomprises removing a liner from a side of the heater pad to expose anadhesive at the side of the heater pad before the back plate is providedat the heater pad and support fixture.
 9. The method of claim 1, whereinattaching the mirror reflective element at the back plate and heater padconstruction comprises removing a liner from a side of the heater pad toexpose an adhesive at the side of the heater pad and pressing the mirrorreflective element against the adhesive at the side of the heater pad ofthe back plate and heater pad construction.
 10. The method of claim 1,wherein attaching the indicator module at the receiving portion of theback plate comprises snap attaching the indicator module at thereceiving portion of the back plate.
 11. The method of claim 1, whereinthe receiving portion comprises a wall structure that at least partiallyreceives the indicator module therein.
 12. A method for assembling amirror reflective element sub-assembly for a vehicular exterior rearviewmirror assembly, said method comprising: providing a support fixturehaving locator pins disposed at apertures thereof and protrudingtherefrom; providing a heater pad at the support fixture, whereby thelocator pins of the support fixture are received through correspondingapertures of the heater pad to align the heater pad at the supportfixture, wherein the heater pad comprises an indicator aperture;providing a back plate at the heater pad and support fixture, wherebythe locator pins of the support fixture are received in correspondingapertures of the back plate to align the back plate at the heater pad atthe support fixture, wherein the back plate comprises an indicatoraperture that, with the locator pins received through the correspondingapertures of the back plate and the heater pad, is aligned with theindicator aperture of the heater pad; attaching the back plate at afirst side of the heater pad; removing the back plate and heater padconstruction from the support fixture; attaching a mirror glasssubstrate at the back plate and heater pad construction via adhesivebetween a side of the mirror glass substrate and a second side of theheater pad, wherein the mirror glass substrate has a mirror reflectorcoated at a side that is opposite from the side that is adhesivelyattached at the second side of the heater pad; providing a laserablation fixture having locator pins disposed at apertures thereof andprotruding therefrom; disposing the mirror glass substrate and backplate and heater pad construction at the laser ablation fixture, wherebythe locator pins of the laser ablation fixture are received through theapertures of the back plate to align the mirror glass substrate and backplate and heater pad construction at the laser ablation fixture; laserablating an indicator icon through the mirror reflector of the mirrorglass substrate at the aligned indicator apertures of the back plate andthe heater pad; after the indicator icon is laser ablated through themirror reflector, removing the mirror glass substrate and back plate andheater pad construction from the laser ablation fixture; and attachingan indicator module at a receiving portion of the back plate, wherebythe indicator module, when attached at the receiving portion of the backplate, is aligned with the indicator icon laser ablated through themirror reflector.
 13. The method of claim 12, wherein the laser ablationfixture comprises structure having an aperture therethrough thatcorresponds with the location of the indicator icon that is laserablated through the mirror reflector when the mirror glass substrate andback plate and heater pad construction is disposed at the laser ablationfixture.
 14. The method of claim 12, wherein the locator pins at thesupport fixture comprise cylindrical pins, and wherein the correspondingapertures of the heater pad and of the back plate comprise a circularaperture and a slotted aperture to provide 4-way locating and 2-waylocating of the heater pad and back plate at the support fixture. 15.The method of claim 12, wherein the locator pins at the laser ablationfixture comprise cylindrical pins, and wherein the correspondingapertures of the back plate comprise a circular aperture and a slottedaperture to provide 4-way locating and 2-way locating of the back plateat the laser ablation fixture.
 16. The method of claim 12, whereinattaching the back plate at the heater pad comprises removing a linerfrom the first side of the heater pad to expose an adhesive at the firstside of the heater pad before the back plate is provided at the heaterpad and support fixture.
 17. The method of claim 12, wherein attachingthe mirror glass substrate at the back plate and heater pad constructioncomprises removing a liner from the second side of the heater pad toexpose the adhesive at the second side of the heater pad and pressingthe mirror glass substrate against the adhesive at the second side ofthe heater pad of the back plate and heater pad construction.
 18. Amethod for assembling a mirror reflective element sub-assembly for avehicular exterior rearview mirror assembly, said method comprising:providing a support fixture having locator pins disposed at aperturesthereof and protruding therefrom; providing a heater pad at the supportfixture, whereby the locator pins of the support fixture are receivedthrough corresponding apertures of the heater pad to align the heaterpad at the support fixture, wherein the heater pad comprises anindicator aperture; providing a back plate at the heater pad and supportfixture, whereby the locator pins of the support fixture are received incorresponding apertures of the back plate to align the back plate at theheater pad at the support fixture, wherein the back plate comprises anindicator aperture that, with the locator pins received through thecorresponding apertures of the back plate and the heater pad, is alignedwith the indicator aperture of the heater pad; attaching the back plateat a first side of the heater pad; removing the back plate and heaterpad construction from the support fixture; attaching a mirror glasssubstrate at the back plate and heater pad construction via adhesivebetween a side of the mirror glass substrate and a second side of theheater pad, wherein the mirror glass substrate has a mirror reflectorcoated at the side that is adhesively attached at the second side of theheater pad; providing a laser ablation fixture having locator pinsdisposed at apertures thereof and protruding therefrom; disposing themirror glass substrate and back plate and heater pad construction at thelaser ablation fixture, whereby the locator pins of the laser ablationfixture are received through the apertures of the back plate to alignthe mirror glass substrate and back plate and heater pad construction atthe laser ablation fixture, wherein the laser ablation fixture comprisesstructure having an aperture therethrough that corresponds with thelocation of the indicator aperture of the heater pad when the mirrorglass substrate and back plate and heater pad construction is disposedat the laser ablation fixture; laser ablating an indicator icon throughthe mirror reflector of the mirror glass substrate at the alignedindicator apertures of the back plate and the heater pad, wherein theaperture of the structure of the laser ablation fixture corresponds withthe location of the indicator icon that is laser ablated through themirror reflector; after the indicator icon is laser ablated through themirror reflector, removing the mirror glass substrate and back plate andheater pad construction from the laser ablation fixture; and attachingan indicator module at a receiving portion of the back plate, wherebythe indicator module, when attached at the receiving portion of the backplate, is aligned with the indicator icon laser ablated through themirror reflector.
 19. The method of claim 18, wherein the locator pinsat the support fixture comprise cylindrical pins, and wherein thecorresponding apertures of the heater pad and of the back plate comprisea circular aperture and a slotted aperture to provide 4-way locating and2-way locating of the heater pad and back plate at the support fixture.20. The method of claim 18, wherein the locator pins at the laserablation fixture comprise cylindrical pins, and wherein thecorresponding apertures of the back plate comprise a circular apertureand a slotted aperture to provide 4-way locating and 2-way locating ofthe back plate at the laser ablation fixture.
 21. The method of claim18, wherein attaching the back plate at the heater pad comprisesremoving a liner from the first side of the heater pad to expose anadhesive at the first side of the heater pad before the back plate isprovided at the heater pad and support fixture.
 22. The method of claim18, wherein attaching the mirror glass substrate at the back plate andheater pad construction comprises removing a liner from the second sideof the heater pad to expose the adhesive at the second side of theheater pad and pressing the mirror glass substrate against the adhesiveat the second side of the heater pad of the back plate and heater padconstruction.